Rivet cutter



Sept. 15, 1942. F. BURNS, JR

:uvm GUTTER Filed March 19, 1941 2 Sheets-Sheet l s, T U N mm md Jm n1 1. w 1% ,.Mwvhn ,A A 1 t l Lw d X m 1 1\\\N\\\\\\\\\\\\M\vwvfwvwvl'hun`\\ u 4 A M /0 I Z3 .Jmb 10 y Y f n. 5% ys 4* n J new f m 51 Sept. 15, 1942.

M. F. BURNS, JR

RIVET CUTTER Filed March 19, 1941 2 Sheets-Sheet 2 lNVENTOR MalandHB1/mad?? Y J/z/m v )15m ATTORNEY,

Patented Sept. 15, 1942 `UNITED STATES PATENT OFFICE e v p 2,296,081' Iarva'r cU'r'rsa Maland F. Burns, Jr., Brooklyn, N. Y. ApplicationMai-m19, 1941, serial No. 384,095 1a Claims. (ci. r1-s) This inventionrelates to rivet cutters, and more particularly to a precision tool fordrilling the heads of rivets so that the rivets can be removed.

Rivets of various types, extensively `used in numerous arts to. securetogether structural parts. In riveting such structural parts, some ofthe applied so that they do not properly hold and secure the structuralparts together, thus necessitating removal of the rivets. It is alsonecessary to remove defective and loose rivets in repairing structuralparts and members in numerous arts. In the aircraftin'dustry, forexample, thousands of rivets are used in each airplane to securetogether the metal plates and bracings which form parts of the wings andfuselage. Since the members andr sheet metal usedare of light gauge,` itis essential that each rivet be firmly and properly positioned so thatthe riveted member will withstand the stress and strain expected of it.In "the airplane industry, it has therefore been. customaryto carefullyinspect each rivet before the: airplane is put into use tospot andlocate 'any defective rivets. Such defective rivets mustgbermoved---and'then replaced bya fully effective'rivet.

No satisfactory devices have I provided by whichl ,deiec` tiv evrivetsjcan be quickly removed without frequentdamage tothe plate shapesand sizes are heretofore been" rivets are defectively possible tomanually hold the drill bit accurately on the rivet head so that thedrill hole will accurately align with the rivet shank. Further,

no means have heretofore been provided to gauge the depth of the holedrilled in the rivet so that the drilled hole will extend tothe 'neckpoint of the rivet and Vno farther. This drilling operation as now usedis dangerous to theV workman due to flying metal shavings, is tediousand timeconsuming, and requires workmen of high skill. The blow torchmethod of removing rivetsl is also tedious and time-consuming, ofteninjures the plate or structural parts which are riveted, and

constitutes a serious fire hazard under certain operating conditionswhere oil or explosive gases are present.

An object of this invention is to provide Va precision instrumentwhereby relatively unskilled workmen can remove defective rivets at-high speed .without damage or injury to the metal plates or structuralparts held by the rivets and without ,enlargementv or distortion of therivet or structural, member whichjthe rivet secures i' ment..ofthe-rivethole. This problem is especially serious in aircraftmanufacture where the metal sheets and members arerrelatively light andof small gauge and where the parts-are subjected to unusually highstresses and which parts wouldr-be seriously weakened by any `darnage tothe plates or members or `enlargements,

of the rivet holes.A Occasionally whole platesrand members or sectionsthereoffpmust be removed as a result of damage loccurringl during theoperation of removing the'defectiv'e rivets meth-f2 odslieretoforepractised. l .l Y, "Chseling and cutting of the rivet heads as nowfrequently practised is not'only tedious and time-consuming but. resultsin damage to the plate or structural part as well as enlargement anddistortion'of the rivet hole. Electric `drills have also been used ,butno` practical guidedevices have been provided for holding the drill onthe rivet head, so that the cutting end of the drill bit often whirlsoif the head of the Y rivet and injures the plate or structural partvsecured by the rivet. It is, further, almost imholes.-

Another object of this invention is 'to provide a highly practical andeicient tool for removing rivet heads from various typesan'd sizes oflrivets. Another objectfof this invention is to provide a tool which maybe connected to a drivingunit andl receive va standard drill bit' andwhich is provided withmeans for automatically center- I ing. the end ofthe bit on the rivet in true alignandwithout-di'stortion, enlargement,or disrlgure-v i mentywith vthe rivetl shank;v

positive means for gauging and limiting the depth of the hole drilledinto `the head oi the rivet and accurately center it in alignment withthe rivet shank. i

Another object of this invention is a rivet cutter equipped with asafety device which discharges the removed shavings and metal particlesin a manner which prevents injury to the operator. L

- A further object of this inventionv is to provide a rivet cutteradapted to` receive and hold drill bits of various sizes, to which aselected assortment of bit guides may be attached for guiding the bit,`centering the bitv on the rivet, and gauging mefdepm of the holearmed-into the rivet i head.

Another object of this invention is to provide means which may beassociated with the rivet cutter fori accurately gauging the operatingposition of the drill bit.

i Various other" objects, features and advantages to provide of theinvention will be apparent from the fo lowing particular description andfrom an inspection of the accompanying drawings.

Although the novel features which are believed to be characteristic ofthis invention will be particularly pointed out in the claims appendedhereto, the invention itself, as to its objects and advantages, and themanner in which it may be carried out, may be better understood byreferring to the following description taken in connection with theaccompanying `drawings forming a part thereof, in which:

Fig. 1 is a side view of the improved rivet cutter shown attached to thechuck of a power drill with the drill bit in position but with the bitguide detached:

Fig. 2 is an enlarged longitudinal cross-sectional view through therivet cutter with the drill bit and bit guide in position to cut theround head of a rivet;

Fig. 3 is a transverse cross-sectional view through the rivet cutter asit appears when looking in the direction of the arrows 3 3 of Fig. 2;

Fig. 4 is a longitudinal cross-sectional view through the lower portionof the rivet cutter, showing the parts as they appear when the drill bithas cut through a round head of a rivet;

Fig. 5 is a fragmentary longitudinal cross-sectional view through thelower portion of the rivet cutter, showing the type of bit guide usedfor drilling a brazer head rivet;

Fig. 6 is a fragmentary longitudinal cross-sectional view through thelower portion of the rivet cutter, showing the type of bit guide usedfor drilling a countersunk rivet;

Fig. 7 is a side view of the rivet cutter partly in. section showing theremovable test cap attached thereto which may be used to determine thebit setting; and

Fig. 8 is an enlarged longitudinal cross-sectional view of the upperportion of the rivet cutter illustrating one type of adjustable chuckwhich may be used to secure the drill bit in the rivet cutter.

Similar reference characters refer to similar parts throughout theseveral views of the drawings and the specification. I

Referring to the drawings, the improved rivet cutter comprises generallya driving member I which is attached to a power unit such as the powerdrill d. The driving member I receives the shank b' of a bit b. One endof the driving member I extends into a normally stationary sleeve 2. Anexpansion spring 3 is telescoped over a section of the driving member Iand rests against a thrust bearing 4 locked within thestationary sleeve2. 'I'he nose end of the stationary sleeve 2 carries a bit guide 5shaped to engage the rivet. head and properly center the cutting end ofthe drill bit.

The driving member I comprises more particularly a head portion IIIhaving a shank II extending from one end thereof. The shank I I isshaped to conveniently nt into a suitable chuck associated with thepower unit d. An elongated body portion of circular cross-sectionextends from the other end of the head portion I0. The body portiongenerally comprises a body section I2'of smaller diameter than the headportion I0 and extending therebelow, a reduced body section I3 ofsmaller diameter than body section I2 extending therebelow, and a bodysection I4 which may have a diameter slightly less than the body sectionI3 and extending therebelow. A relatively elongated bore I5 extendsaxially through the body sections I4. I3 and I2 and into the headportion I0. This bore provides a. socket into which the bit shank b' isinserted.

The bit b is fixedly secured within the socketforming bore I5 by asuitable adjustable securing means which may be an adjustable chuck orin its simplest form may comprise a set screw I6, as shown in Figs. 1and 2. Where a set screw is used to secure the bit in fixed position,the set screw may extend through a threaded opening I1 in the headportion I0 and may be provided with a key socket I8 in which a suitablekey may be inserted to manipulate the set screw and bring the end I3thereof into gripping engagement with the shank portion b' of the bit.

'I'he underside of the head portion I 0 is provided with acircular-shaped recess 2| which receives the upper end of the coiledexpansion spring 3. The upper end of the coiled spring 3 may beremovably retained in recess 2| by means of an overhanging lip 22forming a part of the head portion I0. The coiled spring 3 when fullyextended encloses the body section I2 and a portion of the body sectionI3 but may be compressed so that the entire coil spring is containedupon the body section I2 and above the relatively sharp shoulder 23which defines body section I2 from body section I3.

Thev reduced body section I3 supports the thrust bearing 4'comprisingcircular thrust plates 30 and 33 between which is disposed a circularbearing plate 3| tted with a plurality of ball bearings 32.1'-The thrustplates 30 and 33 and the bearing plate 3| are provided with concentriccircular 'apertures 34 through which the reduced body section I3extends. The concentric openings 34 in thrust plates 30 and 33 andbearing plate3I are of such size that these parts can be telescoped ontothe reduced body section I3 with the lower vend of the expansion spring3 bearing against thrust plate 30. The bearing 4 is retained onthereduced body section I3 by which is telescoped onto the reduced bodysection I4. The upper end of the collar 25 abuts against the shoulder 24which defines the lower end of the body section I3. The collar 25 may bexed to the reduced body section I4 by any suitable means, as by brazingor by a securing pin 26. It will be noted that the diameter of thecollar 25 is slightly greater than the concentric opening 34 in thebearing plate 33, so that when the collar 25 is applied to the bodysection I4, the thrust bearing 4 and the coil spring 3 are retained uponthe body sections I2 and I3 of the driving member I. The bearing 4,however, is free to telescope upon the reduced body section I3 betweenthe shoulder 23 and the upper end of the collar 25. The thrust plate 30can be moved to abut the shoulder 23, in which event the coil spring 3will be compressed and contained upon the shank section I2.

The normally stationary sleeve 2 comprises an enlarged body section 40,the outer surface 55 of which may be knurled to provide a convenienthand grip. The lower end of the body section 40 merges into a taperedshaving-discharge section 4I provided with a threaded nose section 42 atits lower end. The upper end of the body section 4U is provided with acylindrical pocket 43 within which the bearing 4 may seat. Thebearing-receiving pocket 43 adjacent its upper end is provided with acircular recess or groove 44 in which may be positioned a removablelocking key which may be formed of a resilient ring segment 45. When thering segment 45 is positioned within the circular groove 44, as shownmore particularly in Figs. 2 and 3, the ring segment 45 will overlapand-engage the outer periphery of the thrust plate 30 so as to firmlyretain the bearing 4 within the bearing pocket `4I of the normallystationary sleeve 2.

The body section 40 of the sie ve 2 is provided with a relatively largecentral re 48 within V,whichis positioned a bushing 5U. The bushing lllmay be made of bearingmetal and fits tightly in the bore 46. The collar25 has a smooth outer surface and is free to rotatewithin the bushing55. The lower thrust plate 33 of the bearing 4 is normally stationaryduring operationy of the cutter and may be held against rotation by theprovision of suitable projections 48' onthe shoulder 41 of the sleeve,which engage correspondated bit guide is so constructed and proportionedthat the end b of the bit cannot be driven into the rivet farther thanthe neck point rn of the rivet. It will bev noted by referring to Fig. 2that the cutting end of the bit can be advanced only a fixed distance x.which distance is determined by the distance a: between the shoulder 23and the bearing plate I0. In other words, when the driving member I ispushed toward the rivet which crawl up along the bit. A plurality of enelarged openings 52 extendlaterally through the wall of the tapered,section 4I, providing dis-` charge openings for the shavings. `Thecavity i 5I may comprise a tapered bore or a cylindrical bore of thesame diameter as the bore 46 in the body section 40. The nose section 42is provided with a threaded bore 53 for receiving the threaded neckportion 60 of the bit guide 5. e e

The bit guide 5 is a precision instrument shaped to conform toand'engage the head of the rivet to be removed. Thus a separate bitguide 5 is provided for each type and `size of rivet so that rivets ofdifferent sizes having different types of heads may be lremoved by meansof this rivet cutter by merely selecting-and attaching the proper typeof bit guide 5 to the nose end. of the sleeve 2.

e All of the bit guides 5, however, have a threaded shank portion GIIwhich is screwed into the threaded nose 42 of the sleeve 2 and ashoulder 6I against which the flat end 54 of the nose section 42 isadapted to seat. IIhe bitwguides 5 are also provided with a central bore62 through which the end of the bit b may extend. The bore 62 is of suchsize as to rather snugly receive the lower end of the bit to guide thesame without interfering with its free rotation. The lower end of theguide is provided with a pocket and a rim shaped to conform to the rivethead to be removed. The bit guides varyin length as well as in the shapeand contour of the rivet-engaging end thereof. Each` guide may beattached to and removed from the nose 42 of the sleeve 2 by means of asuitable key which may be inserted into a key-receiving opening 63provided in the body of the guide. The threads on the shank portion SIIof the guide are turned so that when the guide is applied to the rivethead the rotation of the driving member will prevent the guide fromloosening. e

In removing a rivet head, it is important that the operating end b" ofthe bit cuts down to the neck rn of the rivet shank but not into theshank, since the bit might otherwise injureor enlarge the rivet hole linthe riveted plates s and s' or otherwise injure or deface the surface ofthe adjacent plate s. The rivet cutter and associagainst the action ofthe expansion spring to the point where the shoulder 2i seats againstthe' upper bearing plate 30, the end b" of the bit will be in its fullyextended position, as shown in Fig. 4, and will project a ilxed distancebelow the end 54 of the nose 42. lWhen pressure on lthe driving member Iis released the expansion spring I will telescope the driving member inthe stationary sleeve 2 in the opposite direction until thelower bearingplate 33 seats against the Yupper end -of the collar 25. In thisposition, the

cutting end b" of the bit is retracted to its greatest` extent in thebit guide 5, as shown in Fig. 2L Thus it will be appreciated that thelongitudinal elength of the body portion of the bit guide, measured fromits shoulder $2 to its rim, determines the distance which the cuttingend of the bit can be telescoped into the rivet head receiving pocket atthe lower end of the bit guide.

The distance s.' which the lower end of the bit is permitted to travelis, however, fixed and determined on each rivet cutter by the distance:c between the shoulder 23 and the top bearing plate 3II when the coilspring 3 is expanded and the bottom plate 33 abuts the endof the collar25.

The bit guide for removing rivets r having round heads rr, 'as shown inFigs. 2 and 4, have a cup-shaped pocket 64 in the end thereof shaped lto generally conform to the outer 4surface contour of the round rivethead rr. The peripheral edge 55 which surrounds the cup-shaped pocket 64is shaped to seat against the adjacent surface of the riveted plate swhich contains the rivet. When the cup-shaped end of the bit guide 5 ispositioned over the round head rr ofthe rivet r, the cup-shaped pocketwill automatically swing the end of the guide into position so as tocompletely pocket the rivet head therein and position the bit bore 52therein s qutirely over the center of the rivet and in line with theshank thereof. The length of the guide body, measured the adjacentsurface of the riveted plate s. The

I body of the guide between the shoulder 6I and the rim 88 is of suchlength as to permit the cutting end b" of the bit b to out into therelatively at brazer head down to the neck rn of the rivet. In thebrazer head rivet the distance betweenthe crown of the brazer headandthe neck rn of the rivet is less than the distance between the crownand the neck of a round head fr on a rivet r of comparable size, andaccordingly the body length of the bit guide, measured from its shoulderBI and its peripheral edge 6B, is correspondingly greater than thedistance between shoulder GI and rim 55 of the bit guide used on roundhead rivets, as shown in Figs. 2 4and 4. Thus by providing a bit guideof the proper body length and proper shaped end pocket, rivet heads ofdifferent shapes and sizes may be drilled and removed.

There is shown in Fig. 6 a bit guide 5 which is shaped to remove theheadsv of countersunk rivets r". The guide used in removing countersunkheads are provided with a cone-shaped pocket 10 which sets over therivet` head and a sharp peripheral edge 'II which seats adjacent theperimeter of the countersunk head rs. In countersunk rivets a fine linedefines the perimeter of the countersunk head from the surface and thecountersunk hole in the plate s into which the sharp peripheral edge ofthe bit guide is adapted to seat. Thus the sharp peripheral edge 1Ifacilitates the location of the bit guide over the countersunk head sothat the bore 62 thereof is in axial alignment with the body of thecountersunk rivet r. To remove such a countersunk head the cutting endb" of the bit drills through the countersunk head rs down to the neckportion rn of the rivet, so that when the countersunk head has beenfully drilled, the cutting end b" of the bit will project a distancebeyond the sharp edge 'II of the guide equal to the depth of thecountersunk head rs. Thus the length of the body of the guide used forremoving countersunk heads, measured by the axial distance between theshoulder 6| of the guide and the gripping edge of the guide, would besomewhat less than the body length of the guide used in removing brazerheads, as shown in Fig. 5, or round heads, as shown in Figs. 2 and 4.

The rivet cutter kit is equipped with a number of guides, each shaped tofit a certain size of rivet of a certain head shape. In aircraftmanufacture, for example, approximately twelve different types and sizesof rivets are used, which may be classified into four different shankdimensions having diameters respectively of 32 inch, 1A; inch, 5% inchand T35 inch. A single rivet cutter of the type shown in Figs. 1 and 2may be designed to receive four diiferent bits having correspondingdiameters. Thus the bore I5 of the driving member I may be of such sizeas to snugly receive the shank of the largest or Tae inch size bit. Inorder that the smaller bits will snugly seat within the bore I5, thesmaller bits may be provided with correspondingly enlarged shankportions b so that each shank portion b will have a diameter ofapproximately 1%; inch. Thus the shank portions b' of each of the fourbits will snugly fit within the bore I5 so that the bit will be properlycentered within the bore and fixedly held by suitable gripping means,such as the set screw I6.

In aircraft manufacture, for example, rivets of three different headshapes are usually employed, such as rivets with round heads rr, brazerheads rb and countersunk heads rs, making a total of three differenttypes of rivets in four different sizes, or a total of twelve differentrivets. The cutter kit would therefore be equipped with twelve differentguides suitably marked and identified with the type of rivet with whicheach is to' be used and, if desired, the kit may also be equipped withfour bits of the different sizes. Thus a workman equipped with a powerdrill driven either electrically or by compressed air and a cutter kitequipped with a single rivet cutter unit, four bits of the above sizes,and twelve bit guides, would be prepared to remove the heads from alldefective rivets of the sizes and types used in aircraft manufacture.

'I'he kit may also be provided with a test cap 90, as shown in Fig. 7,which accurately determines the proper position of the cutting end b" ofthe bit positioned withinv the rivet cutter. It will be appreciated thatwhen the cutting end b of the bit is sharpened, the length of the bitbecomes shortened so that the bit shank b' will have to be fixed in thebore I5 in the proper position. Since the total telescoping movement :cof the cutting end b" of the drill bit is fixed and determined for eachrivet cutter, it will be appreciated that the distance which the lowerend of the bit projects beyond the end 54 of the nose 42 when it is inits extreme retracted position must be constant. Thus if the bit, ofwhatever length, is so set in the rivet cutter that its end b" projectsbeyond the end 54 of the nose 42 a fixed distance, as shown 'in Figs. 1,2, 5 and 6, the bit will operate with precision and accuracy with all ofthe various bit guides with which the kit is equipped. When the coilspring 3 is fully expanded to carry the bit to its full retractedposition, the end of the bit should project beyond the lower end 54 ofthe sleeve 2 the distance shown in Figs. 1, 2, 5, 6 and 7 when the bitis in its -full retracted position. The proper setting of the bit may bequickly done by screwing the test cap into the threaded bore 53 in thenose portion 42 of the sleeve member 2. The test cap 90 is provided witha shoulder 9| which seats against the end 54 of the nose 42 when itsthreaded shank 92 is fully screwed into the threaded bore 53 of thenose. The test cap 90 is provided with a bottom wall 93 which closes theend of a bore 94 into which the end of the drill bit may extend. Asocket hole 96 may be provided in the body of the test cap 90 into whicha suitable tool may vbe inserted to turn the test cap onto the threadednose 42.

To adjust the shortened bit in the rivet cutter, the drill bit isinserted into the socket I5 in the driving member I and the test cap 90screwed into place. A small bore I5 extends through the shank II of thedriving member I into which a suitable instrument may be inserted whichengages the top end of the bit and which may be used to push the bitdownwardly so that its cutting end b" telescopes into the socket 94 ofcap 90 and seats against the inside surface 95 of the cap member. Thebit clamping means, such as the set screw I6, is then tightened to holdand retain the bit tightly against the bit shank b to hold and fix thebit in this position. The test cap 90 is then removed and the selectedbit guide put in its place. The operating end oi' the bit is thenaccurately and precisely positioned for use with all of the bit guidesin the kit and with the assurance that the cutting end of the bit willdrill through all the various rivet heads which the guides are adaptedto fit, and will drill no farther than the neck point m of the rivet.

If desired, a device which forms a permanent part of the rivet cuttermay be provided for sliding the bit b in the socket I5 of the drivingmember. Such a device may comprise a shank screw |00, as shown in Fig.8. In this construction, the shank II of the driving member I may beprovided with a threaded bore |0| which is adapted to receive thethreaded portion |02 of the shank screw |00. Shank screw |00 is providedwith a shank portion |03 which snugly fits within a bore |04 in the headportion |05 of the driving member I. By manipulating the shank screw|00, as by means of a socket wrench inserted intosocket aperture intheir respective sockets |09 i trunk portion is provided with the bitshank b 2,296,087 the endvof the screw,.the lower` end |01 of fthe screwmay be advanced or retracted. The lower `end illl of the `shank screw|00 is adapted to seat against the end ofthe shank b' ofthe bit b, sothat when the shank screw |00 is manipulated the cutting end bf? of thebit may be pushed into seating 4engagement with the inside surface 35 ofthe test cap 00, as shown in Fig. '1.

The driving. member imay, if desired, be

equipped with a suitable chuck for gripping the shank b' of the bit, inplace of the setscrew I6 shown in Fig. Ziwhe'rethe smaller sized rivetsare used, as in a craft manufacture, the set screw I6 has been found tobe amply sufficient to rigidly secure the .drill bit in fixed positionin driving member i. Wherever large sized rivets are ltobe removed, itmay be desirable to provide the driving member with a chuckto hold thebit in fixed position. There is shown in Fig. 8 one type of chuck whichmay be associated with the driv. ing member i. i

The chuck assembly shown in Fig. 8 is formed of two separable partswhich together form the driving member In this construction a stemportion |08 extends above the body section I2 which carries the coilspring 3, with the bit bore I extending through the stem section |08. A

.plurality of sockets |09, preferably three in number, are provided atthe upper end of the stem section |08, each ||0. The upper end of thestem section is provided with a tapered surface beyond which aperipheralportion ||2 of each ball ||0 pro;|ects. The balls ||0 are sopositioned and. seated in that a portion of the ball f is adapted togrip the stem b of -the bit. Sternsectionv |08 is provided with athreaded body I3 which terminates in a shoulder lil. A ||5 having asmooth outer surface and cylindrical in form, projects below theshoulder H4 .and extends down to an outturned flange portion ||8 whichcarries the circular` lip 22 for retaining the upper end of the coilspring 3 in the recess 2|..

A removable head |05 is provided with a downwardly extending skirt |20which defines a pocket |2| into which the stem section |08 extends. Thepocket |2| 'is provided with atapered tubular inner surface |22 adaptedto seat against the outer .portion of theballs ||0. The skirt |20 isadapted to retain a steel ball f fectively remove defective rivets.

-be appreciated that other types 5 the tapered cam surfaces |24 pressthe balls ||0 into gripping eng-agement( with the bit shank b.Preferably only three balls ||0 are used so that the bit shank isgripped at three points. `It will be appreciated that the larger the bitstemthe less distance the head section |05 can be turneddown on thethreaded stem section |08, and the smaller the tdiameter ofthe bit shankthe farther the head section |05 can be turned down on the threaded stemsection |08. Thus the chuckA I shown in Fig. 8 may bermade to retain agrip on bit Shanks of various diameters. It will be noted that thethreads on the threaded portion |23 of tlie head skirt |20 are turned tocorrespond with the rotation of the shank when driven by the power unit,so that the heavier the bit load the greater will be the grip' exertedby the balls |I0 on the bit shank b. While the chuck arrangement shownin Fig. 8 provides an effective meansfor rigidly securing bit shanks ofvarious diameters in the driving member I, it will of chucks may be usedfor that purpose.

The rivet cutter constructed as above described provides a precisioninstrument whereby rivet heads can bev accurately and precisely drilledat high speed. It is a tool which can be safely operated by unskilledworkmen-to quickly and ef- It is only nec.. essary to know the type andsize of rivets to be removed, select the corresponding drill bit size,fix

tapered surface |22, which threaded portion 4is l adapted to be screwedover the threaded portion ||3 of the stem section |08. The lower end ofthe skirt |20 is provided with a removable rim member |24 having athreaded flange portion |25 adapted to be screwed onto the end of thethreaded portion |23 of the skirt. II'he rim member |24 a circularopening through which the trunk portion ||5 of the stem |08 extends.The-fhead section |05 cannot be removed from the stem section `|00except by turning the rim member |24 .off from the end of the sleeve`|20. The head'` section |05 may be pr vided with an internal cavity |26into which the upper end of y may extend so as to increase thepermissible longitudinal adjustment of the bit.

To remove the bit fromthe chuck shown in Fig. 8, the head section |05 isturned so as to raise the tapered surface |2| thereof away from theballs ||.0 so that the balls ||0 can move outwardly in their sockets |09and release `the bit. When the `bit is reinserted, the head section |05is turned Ldown over the stem section |08. until yond the neckpoint .rnof the rivet. AWhen the remove. 4When the proper bit guide 5 the bit sothat it it in the socket of the driving member with the position of thecutting end of the drill bit gauged by the gauge cap 90, and then applythe proper bit guide 5 which is numbered and marked'with the type andsize of rivet it is constructed to has been applied to the nose end ofthe sleeve 2, the operator throws `on the power which operates thedriving unit and places the pocket end of the bit guide over the rivethead.` `'The pocket end of the bit4 guide is so shaped that the guide isself` centering on the rivet head when the driving member is pressedtoward the rivet head by exerting `a light push on the driving unitwhich is held in one hand.` The other hand of the operator holds theknurled sleeve 2, whose interior surfaces are spaced a substantialdistancev from will not heat.

The shavings cut from the rivet head follow the contour .0f the rivetinto the ber 5| from-which they larged opening 52. The

drop vout through the ensleeve 2 is so constructed that they drop outthrough theopening 52 without velocity. It is Vtherefore unnecessary forworkmen using this tool to wear either` goggles or helmets, which havegenerally been worn when cutting the rivets with tools heretofore forthis purpose.

It will be further noted that the bit guide 5 is so constructed andproportioned that the cutting end of the bit can be driven down to butnot beneck point has been reached the shoulder 22 will seat against thethrust plate 30 of the bearing vso that it is impossible to cut fartherinto the rivet. The rivet head is fully and completely cut when thedesignated blt guide is attached to the nose end of the sleeve.This'rivet cutter is substantially foolproof in operation and can besafely operated by relatively unskilled workmen with assurance that therivet headwill be properly andaccurately cut downto theneck point of therivet. the head of the rivet will and` no farther, so that enlargedchamemployed drop 01T or can easily be pushed oi and the rivet shankdriven out of to surrounding portions o1' the riveted plate and withoutenlarging or misshaping `the rivet hole. Rivet heads can be removed withthis eicient tool in a very few seconds. An industrious workman canremove the heads .from thousands of defective rivets in a working daywith this tool.

The improved rivet cutter herein disclosed can be constructed insubstantially any size to remove `numerous diierent types, kinds andsizes of rivets which must be removed during the construction and repairof aircraft, ship hulls, structural framing,railroad cars and vehicles,and in numerous other arts where rivets are employed to securestructural parts together. and injury to workmen are completely avoided,which is a serious drawback to use o t cutting, drilling, chipping, andblow torch -tools heretofore employed for this purpose. Furthermore, therivets can be removed by relatively unskilled workmen at several timesthe speed at which this operation can be accomplished by the.instrumentalities heretofore provided ior this purpose and with theassurance that the rivet holes left by the rivets will not be distortedor enlarged or the surface of the structural parts injured or disgured.

While certain novel features of the invention have been disclosed andare pointed out in the annexed claims, it will be understood thatvarious omissions, substitutions and changes may be made by thoseskilled in the art without departing from the spirit of the invention.

What is claimed is:

1. A rivet cutter including, a driving member having a `driving shankfor attachment to a power. unit and a body section having'a bitreceiving socket, rmeans for removably securing the bit in said socket,anon-rotating guide sleeve, a thrust bearing seating in said sleevehaving an aperture through which said bodysection extends, means forlimiting the longitudinal separating movement oi' said driving memberand guide sleeve, an expansion spring surrounding said `body section andinterposed between a shoulder on said driving member and said thrustbearing for yieldingly holding said driving member and sleve relativelyseparated to the extent permlttedby said limiting means, and a. bitguide at the end of said sleeve having a passage to receive and"` guidethe bit secured in the socket of said driving member. 2. A rivet cutterincluding, a driving member Further, re hazardY the rivet hole withoutdamage having a driving shank for attachment to a power unit and a bodysection having a bit .receiving socket, means for removably securing thebit in said socket, a `non-rotating guide sleeve, a thrust bearingseating in said sleeve having an aperture through which said bodysection'extends, means for limiting the longitudinal "separatingmovement oi' said driving member and guide sleeve, an expansion springsurrounding said body section and interposed between 'a shoulder on saiddriving member and said thrust bearing for yieldingly holding said,driving member and sleeve relatively separated to the extent permittedby said limiting means, and a bit guide removably secured tc the end ofsaid sleeve having a passage to receive and guide the bit secured in,the socket of said driving member, the outer endol said drill guidebeing contoure'dto nt a rivethead.

; 3. A rivet`cutter comprising, a driving member having a driving shankat one end for engagement in a bit chuck and a posite end having a bitreceiving socket, means body section at the op-l said bit in .saidsocket, a a bearing telescoping removably secured to for removablysecuring non-rotating guide sleeve, over said body section and saidsleeve, means associated with said body seci tion for limiting thelongitudinal separating movement of said driving member and guidesleeve, an expansion spring interposed between a ment ofsaid bearing,

bore receiving a portion of said body section,

means for securing said bearing to said sleeve..

means for yieldably holding said driving member and Aguide sleeverelatively separated to the extent permitted by said limiting means, anda bit guide removably secured to the end o1' said sleeve, said bit guidehaving a passage to receive and guide the bit and an outer contoured tofit a rivet head.

6. A rivet cutter comprising, a driving member having a shank portionfor insertion finto a drill chuck and a stem portion having an elongateddrill receiving socket, a non-rotating guide sleeve l receive and guidethe drill portion having a conical seat to accommodate a rivet head anda rim to fit about a rivet head and centralize the drill on said rivet.

receiving said stem portion and in which said stem is longitudinallyshiftable. and a drill guide at the end of said sleeve having a passageto and an outer end portion having a conical seat to accommodate a rivethead and a relatively sharp edge to iit about a rivet head andcentralize the drill on said rivet.

8. A rivet cutter comprising, a driving member having a driving shankfor attachment to a chuck and a body section providedlwith an endportion elongated bit receiving socket, a non-rotating guide sleeve, abearing telescoping over said body section, said sleeve having a pocketwithin which said. bearing seats, means for securing said bearing insaid pocket, an expansion spring positioned between a shoulder on saiddriving member and said bearing for relatively shifting the drivingmember and sleeve in a longitudinal separating direction, shoulders onsaid body section for limiting the extent of such longitudinalseparating movement, and a bit guide at the end of said sleeve having apassage receiving and guiding the bit and a rim in the end of the samefor centering the guide on a rivet head.

9. A rivet cutter comprising, a driving member having a driving shankfor attachment to a chuck and a body section provided with an elon'-gated bit receiving socket, a non-rotating guide sleeve, a bushing fixedin said guide sleeve into which said body section extends, a bearingtelescoping over said body section, said sleeve having a pocket withinwhich said bearing seats,

means for securing siad bearing in said pocket,

an expansion spring positioned between a shoulder on said driving`member and said bearing for relatively shifting the driving member andsleeve in a longitudinal separating direction,`

shoulders` on saidbody section for limiting'the extent of suchlongitudinal separating movetachment to a chuck and a stem at theopposite end provided with a drill receiving socket, means for removablysecuring said drill in said socket,

atively shifting the driving member and sleeve in a longitudinalseparating direction,l means for limiting the extent of such shifting'movement,

andja drill guide removably secured to the end of said sleeve having a,passage receiving and ment, and a bit guide at the end of said sleevehaving a passage receiving and guiding the bit and a rim on theend ofthe same for centering the guide on a rivet head.

10. A rivet cutter comprising, a driving member having means forattaching it to a driving unit and a body section having a bit receivingsocket, means for removably securing a bit in said socket, anon-rotating guide sleeve having an enlarged section into which saidstem is longitudinally shiftable and a tapered nose section, means forshifting said driving member and guide sleeve in a longitudinalseparating direction, means for limiting the extent of said shiftingmovement, and a bit guide secured to the end of said tapered section,said tapered section having an enlarged shavings receiving chamber andshavings outlet ports leading therefrom.

11. A rivet cutter comprising, a driving member having means forattachment to a driving unit and a body section having abit receivingsocket, a non-rotating guide sleeve having an enlarged section and atapered-section, a bearing telescoping over said body section andsecured to the enlarged section of said sleeve, an expansion springseating between a shoulder on said driving member and the bearing xed tosaid guide sleeve for relatively shifting the driving member and sleevein a longitudinal separating direction, means for limiting the extent ofsaid shifting movement, and a drill guide secured to the tapered sectionof said sleeve having a. passage receiving and guiding the bit and ameans at the end thereof for centering the guide over a rivet head, saidtapered section having an enlarged shavings receiving chambercommunicating with the passage in said guide and a plurality of outletports extending laterally from said chamber.

12. A rivet cutter comprising, a driving member having a `driving shankat one end for atguiding the drill and a'pocket in the end of the samefor receiving a rivet head having a surrounding relatively fine edge.

13. For use with a drill bit fixed to a driving member having apredetermined telescoping movement in a relatively stationary sleeve, ofa bit guide for centering the cutting end of the bit on a rivet head,means for removably securing said guide to the end of said sleeve, saidguide having a passage for receiving and guiding the cutting end of thebit and an outer-end portion vcontoured to iit a rivet head.

14. For'use with a drill bit fixed to a driving.

member having a predetermined telescoping movement in a relativelystationary' sleeve, of a bit guide for centering -the cutting end of thebit ona rivet head, means for removably securing said guide to the endof said sleeve, said guide having a passage for receiving and guidingthe cutting end of the bit and an end portion contoured to fit the roundhead of a rivet. 15. For use with a drill bit fixed to a drivingmemberhaving a predetermined telescoping movement in a relativelystationary sleeve, of a bit guide for centering the cutting end of thebit on a rivet head, means for removably securing said guide to the endof said sleeve, said guide having a passage for receiving and guidingthe cutting end of the bit and an end portion contoured to fit thebrazer head of a rivet.

16. For use with a drill bit iixed to a driving member having apredetermined telescoping movement in a relatively stationary sleeve, ofa bit guide for centering the cutting end of the bit on a rivet head,means for removably securing said guide to the end of said sleeve, saidguide having a passage for receiving and guiding the cutting end of thebit and an end portion contoured to fit the countersunk head of a rivet.

17. For use with a drill bit fixed to a driving member having apredetermined telescoping movement in a relatively stationary sleeve, ofa bit guide for centering the cutting end vof the bit on a rivet head,means for removably securing said guide to the end of said sleeve, saidguide having a passage for receiving and guiding the cutting end of thebit and an outer end portion contoured to t the rivet head, the axiallength of the body of said guide being such as to permit the cutting endof the bit to drill into a rivet head down to the neck point of therivet.

18. For use with a drill bit adjustably secured to a driving memberhaving a predetermined telescoping movement in a relatively stationarysleeve, of a gauge cap adapted to be removably attached to the end ofsaid Asleeve for locating the position of the cutting end of said bit.

MALAND F. BURNS, Jn.

